Bearings Flashcards
What is the purpose of bearings?
Enables rotational or linear movement while reducing friction and handles stress.
What do ball bearings do?
Carries the weight of the load, this force drives the bearings rotation.
What are the two kinds of loading?
Radial (shaft sidewards loads) and Axial/Thrust loads (shaft longitudinal loads)
What are compound loads?
Loads that are in both directions Axial and Radial.
What does frictional resistance do?
Produces heat which impacts performance.
What loads do ball bearings handle?
Axial or Thrust loads
What loads do roller bearings handle?
Radial loads (sideward loads)
Roller bearings are used for long life and endurance for?
Heavy and shock loads. They have a larger load carrying capacity.
Types of plain bearings?
Journal bearings, spherical plain bearings and air bearings.
Journal bearings consist of?
Load carrying cylindrical inserts made with white metal called Babbitt.
What does oil do in journal bearings?
Oil supports the shaft preventing metal to metal contact.
How does oil film carry?
The hydrodynamic principle, there must be some clearance with the stationary part and rotating part.
Spherical bearings allow?
More or less angular alignment correction.
Spherical bearings are not intended for?
Rotation
Spherical bearings can have grease nipples but are mainly?
Maintenance free and are self lubricating.
Air bearings use what to provide low friction load bearing interface between surfaces?
A thin film of pressurised air.
Rolling element of ball bearings?
Steels balls rotate in grooved raceways
Rolling element of Roller bearings use?
Cylindrical, tapered and spherical rollers running in suitably shaped raceways
What loads do ball bearings and tapered roller bearings both accept?
Both radial and axial (thrust) loads
Other types of roller bearings accept only?
Radial loads
Ball bearings consist of?
Inner and outer race separated by hardened steel balls
Ball bearings are designed for?
Radial or axial (thrust) loads or a combination of both. Are rigid or self aligning.
Roller bearings are normally only used for?
Radial loads but can compensate for linear expansion of the shaft or housing.
Three types of Roller bearings
Cylindrical
Spherical
Tapered
Taper roller bearings are made from?
Hardened steel
Needle roller bearings are thin cylindrical rollers that’s length is
Four times longer than the diameter
Needle roller bearings can support?
A greater load and require less clearance between the axle and surrounding structure
Needle bearings are used for?
Low speeds or swinging movements. And for fluctuating and surge loads
Needle bearings support only?
Radial loads
Thrust bearings are designed for retaining?
Axial forces
What type of bearing must not work unloaded?
Thrust bearings , it prevents slipping of the balls
Cylindrical roller thrust bearings must not be operated unloaded because
You must prevent slipping of rolling elements
